fn main() {
    var clock = fn():int {
        return 1682261163
    }

    var morning = fn(fn():int callback) {
        var t = callback()
        print('timestamp=', t, '\n')
    }

    morning(clock)


    morning(fn():int {
        return 1682262975
    })

    var callback = fn():int {
        return 1682263024
    }

    morning(callback)
}